Stop in for a cup of coffee
Good evening folks!
Spent the day checking and diagnosing all the vacuum HVAC controls in the GTS with my new vacuum tester. Looks like the control switches are fine and the AC doors all work like they should. The problem I found is that none of the heater and defrost controls work. It won't develop or hold any vacuum when those are selected.
I'm going to have to trace those when I tear the dash apart over the Winter. I suspect the previous owner disabled those controls by disconnecting the vacuum lines to those doors. I'm guessing he wanted all air flow to always go through the AC being down south in the muggy moist air of the Mississippi river and Gulf coast.